An erj flight crew encountered what appeared to be wave action when starting a descent and; instead;...

Narrative:

We were assigned an initial cruising altitude of 33;000 ft. Once we reached our initial altitude we were in a haze layer and there was pretty consistent light chop and thought that if we went up to FL370 we might get a better ride have a better view of any weather ahead of us. We climbed to FL370 and were still in the haze but had no returns on our radar screen. It was mostly smooth with some rare ripples of light chop and since we had been dealing with the weather/turbulence earlier in the day the captain decided to leave the seatbelt sign on. We were in communications with the flight attendant about the possibility of turbulence the whole flight. ATC assigned us M.77 for spacing into dca. As we were over the luise intersection we were issued a descent clearance to FL310. I spun in the altitude; verified it with the captain; and set a descent rate of 1;000 FPM on the vs selector. As soon as we started our decent the aircraft pitched up and began about a 2;500 FPM climb. I instantly pulled the power to idle and overrode the autopilot to put us into a stable descent attitude and once the aircraft was established in a stable descent I reengaged the autopilot. During all this the captain advised ATC that we were unable to hold altitude and that we would advise when we were established back on our descent. The whole event only lasted 10 or so seconds and after that the flight continued smoothly and without incident. The turbulence wasn't the normal jarring bumps as it was more of a gentle sensation as if you were riding atop a wave. Dispatch called us a minute or so after the event to tell us that we should be crossing the worst of the weather in the next few minutes. While the captain was talking to dispatch I advised ATC that we would be unable to maintain M.77 due to the weather and slowed the aircraft. No passengers or crew were injured and there weren't any conflicts with traffic. The aircraft operated normally throughout the whole flight and event. We knew we were crossing weather and were very active in monitoring the situation. We made multiple calls to ATC asking about how the rides were at our altitudes. All SOP's were complied with.

Original NASA ASRS Text

Title: An ERJ flight crew encountered what appeared to be wave action when starting a descent and; instead; gained 500 FT prior to establishing a controlled descent.

Narrative: We were assigned an initial cruising altitude of 33;000 FT. Once we reached our initial altitude we were in a haze layer and there was pretty consistent light chop and thought that if we went up to FL370 we might get a better ride have a better view of any weather ahead of us. We climbed to FL370 and were still in the haze but had no returns on our radar screen. It was mostly smooth with some rare ripples of light chop and since we had been dealing with the weather/turbulence earlier in the day the Captain decided to leave the seatbelt sign on. We were in communications with the Flight Attendant about the possibility of turbulence the whole flight. ATC assigned us M.77 for spacing into DCA. As we were over the LUISE Intersection we were issued a descent clearance to FL310. I spun in the altitude; verified it with the captain; and set a descent rate of 1;000 FPM on the VS selector. As soon as we started our decent the aircraft pitched up and began about a 2;500 FPM climb. I instantly pulled the power to idle and overrode the autopilot to put us into a stable descent attitude and once the aircraft was established in a stable descent I reengaged the autopilot. During all this the Captain advised ATC that we were unable to hold altitude and that we would advise when we were established back on our descent. The whole event only lasted 10 or so seconds and after that the flight continued smoothly and without incident. The turbulence wasn't the normal jarring bumps as it was more of a gentle sensation as if you were riding atop a wave. Dispatch called us a minute or so after the event to tell us that we should be crossing the worst of the weather in the next few minutes. While the Captain was talking to Dispatch I advised ATC that we would be unable to maintain M.77 due to the weather and slowed the aircraft. No passengers or crew were injured and there weren't any conflicts with traffic. The aircraft operated normally throughout the whole flight and event. We knew we were crossing weather and were very active in monitoring the situation. We made multiple calls to ATC asking about how the rides were at our altitudes. All SOP's were complied with.

Data retrieved from NASA's ASRS site as of April 2012 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.

Attributes
ACN	942105
Time
Date	201104
Local Time Of Day	1801-2400
Place
Locale Reference	ZOB.ARTCC
State Reference	OH
Environment
Flight Conditions	IMC
Light	Dusk
Aircraft 1
Make Model Name	Embraer Jet Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	Cruise
Flight Plan	IFR
Person 1
Function	First Officer Pilot Flying
Qualification	Flight Crew Commercial
Person 2
Function	Captain Pilot Not Flying
Qualification	Flight Crew Air Transport Pilot (ATP)
Events
Anomaly	Deviation - Altitude Excursion From Assigned Altitude Deviation - Procedural Clearance Inflight Event / Encounter Weather / Turbulence

An erj flight crew encountered what appeared to be wave action when starting a descent and; instead; gained 500 ft prior to establishing a controlled descent.